EFFECTS OF FARM-MANAGEMENT PRACTICES ON CATTLE GRAZING BEHAVIOR AND THE POTENTIAL FOR TRANSMISSION OF BOVINE TUBERCULOSIS FROM BADGERS TO CATTLE

Despite the large body of circumstantial evidence to suggest a link, t ile means by which bovine tuberculosis is passed from badgers to cattl e remains unclear; pasture contamination with the urine, faeces and/or sputum of infectious badgers is believed to be the main route of tran smission. Therefore the behaviour of grazing cattle was studied to det ermine whether they avoided investigating and/or grazing pasture conta minated with badger excreta, and whether different farm management pra ctices enhanced the potential for disease transmission. Active latrine s were avoided by most cattle until the sward length in the rest of th e field was reduced, after which there was an increasing likelihood th at active badger latrines would be grazed. Most of the cattle grazed a ctive badger latrines, but cattle of low rank within the herd glazed l atrines more heavily. Farm management practices that reduced the avail ability of long swards shortened the period of investigative behaviour and greatly enhanced the risk that cattle would graze active badger l atrines. Cattle were more likely to graze pasture away from latrines t hat was contaminated either with badger urine or single faeces. Becaus e bacilli remain viable in the soil for up to 2 years, there is the po tential for bacilli to accumulate at active badger latrines, and these could pose a significant risk to cattle, even when the latrine is no longer being used by badgers. Cattle readily grazed the lush sward at disused latrines, during which they could ingest contaminated soil; th e amount of soil ingested increases as sward length decreases.